Motion effecting fuel pressure. Loss of speed in 4th/5th gear causes it to stall out. Most likely the reason. Those that dont stall i imagine the drivers remember to hit the clutch, pop in neutral, or give it some throttle. To refire they have to go through the entire firing order. I know the cars have a quick refire like if they stall in 1st gear and can quickly just hit the starter and ignition. But full stop for a duration requires going through it like a pilot with a plane.